EXPERIMENTAL STUDY ON BUOYANCY-INDUCED CONVECTION IN OPEN CELL ALUMINIUM METAL FOAMS

This paper presents the results of an experimental study on buoyancy induced convection in open cell aluminium foams attached to a one sided heated plate. The foam samples had porosity of around 90% and pore densities of 2, 4, 8 and 16 pores per cm. (PPC). The experiments were conducted under different orientations ranging from horizontal (heated from below) to vertical (heated from side). The heat transfer rates from the heater plate was measured and found to be a strong function of pore density and orientation as well as temperature gradient. In all the cases, the heat transfer rate was found to be superior to that of a vertical flat plate. For a given porosity and height the samples with larger pore sizes were found to be more effective. Finally the effective heat transfer coefficient was plotted in the form of Nusselt number as a function of Rayleigh number to capture its dependence on the foam geometry and boundary condition.